java.util.ConcurrentModificationException

Java Map 對象不能在迭代時進行刪除操作

示例如下：

<span style="white-space:pre">	</span>@Test
	public void removeTest(){
		Map<String,Object> map = new HashMap<String,Object>();
		map.put("hello","world");
		map.put("kitty", "mvane");
		
		for(String str : map.keySet()){
			System.out.println(map.get(str));
		}
		
		for(String str : map.keySet()){
			map.remove(str);// 拋出 java.util.ConcurrentModificationException
		}
	}
	
	@Test
	public void removeTest2(){
		Map<String,Object> map = new HashMap<String,Object>();
		map.put("hello","world");
		map.put("kitty", "mvane");
		
		for(Iterator<String> iterator = map.keySet().iterator();iterator.hasNext();){
			System.out.println(map.get(iterator.next()));
		}
		
		for(Iterator<String> iterator = map.keySet().iterator();iterator.hasNext();){
			String str = iterator.next();
			if(str.equals("kitty")){
				iterator.remove();
				map.remove(str);
			}
		}
		
		for(Iterator<String> iterator = map.keySet().iterator();iterator.hasNext();){
			System.out.println(map.get(iterator.next()));
		}
	}